P127Assessment of fetal anatomy in the first trimester using two and three dimensional ultrasound

Objectives To study if a complete anatomical survey of the fetus at 12–13 weeks gestation can be achieved using stored volumes acquired by a 3D scanner. Subjects/methods One hundred and twenty-two consecutive women at 12–13 weeks gestation who had a scan in our unit. A complete survey of the fetal anatomy was attempted by transabdominal and if needed transvaginal 2D scanning. Then using the 3D transvaginal probe (Kretz 530D) two volumes containing the fetus were acquired. A complete anatomical survey was attempted using the data from these volumes (excluding the anatomy of the heart). Results A complete anatomical survey was achieved in 93% (113/122) of cases with the 2D scanning comparing to 71% (86/122) with the 3D volumes (statistically significant difference, P < 0.01). The nuchal translucency was measured in 97.5% of cases with 2D scanning and in 82% with the 3D volumes. The mean time to perform the 2D scan was 15 min (SD: 4 min) while the time to examine the stored volumes was 6.6 min (SD: 2.66). Using the stored volumes we obtained the required views in 8 of the 9 cases in which the survey was incomplete by the 2D scan. Discussion Real time 2D scanning is still the best way to examine the fetal anatomy in the first trimester. However, 3D scanning can be a useful addition to clinical practice providing views not easily obtained by conventional 2D scanning. It can potentially minimise the actual scanning time and provides an excellent way to store scanned data.